Refrigerating apparatus



' Feb. 7, 1933. R. w DAVENPORT 1,896,612

REFRIGERATING APPARATUS Filed Jan. 18, 1927 INVENTOR. 7 25/7500? Wfiare/zaorf A TTORNE Y.

Patented Feb. 7, 1933 v UNITED STATES PATENT OFFICE nANsom w.' DAVENPORT; or DETBOIT, MIGHIGAN, Assrenon 'ro cnIcAeo PNEUMATIC moor. COMPANY, on NEW vonx; N. Y., A CORPORATION or NEW JERSEY BEFRIGERATING APPARATUS Application filed January 18,1927. Serial No. 161,730.

This invention relates to the art of producing refrigerating effects artificially with particular reference to systems operating on the conventional or Rankine cycle. It comprises both a process and apparatus adapted for practicing the process, and has been de-' veloped with the small domestic outfit or machine particularly in mind but its application is by no means confined thereto.

have been heretofore constructed and operated so as to have liquid refrigerant in both the warmer and colder parts of the system at all times, thus maintaining a high pressure in the condenser or high side of the system and a low pressure in the evaporator or low side of the system. This pressurecondition results from the customary practice of storing liquid refrigerant in a condenser or receiver at room temperature and feeding it only in such amounts as will keep a constant level or amount in the evaporator. Since evaporable liquid is always present in the higher temperature part of the system, the

5 pressure thereinis always higher than in the refrigerator or evaporator. The pump or compressor must accordingly be started up against a great pressure head which is very objectionable in the case of the domestic machine which is arranged for frequent starts and stops, and where economy of operation is an important consideration.

One object of the invention is to adapta Rankine cycle refrigerating system to be operated by a motor having a moderate or low starting torque and drawing a low or moderate starting current from the supply mains. Another object is to reduce the high side pressure when such a system shuts down. An- 4') other object is to effect the above results without impairing the operating characteristics of the system. Other objects will be appariant from the detailed description which folows. I

The invention involves the novel principle -so arranged the high side pressure falls sub- All Rankine cycle systems so far as known 1 of storing all the liquid refrigerant in the low temperature side of the system when the machine shuts down and causin the high temperature side to dry out. ith the system stantially to that of the low side when the motor stops and the starting load on the m0- tor is correspondingly relieved.

The accompanying drawing illustrates a preferred form and arrangement of apparatus for practicing my improved process, the single view being a front elevational view with'certain parts in section of a self-contained refrigerating outfit for domestic use.

The illustrative embodiment of the invention discloses apparatus forming a refrigerating system .operating'on the Rankine cycle and associated with a refrigerator or cabinet A having an insulated chamber a for the storage of food or other perishable articles. The apparatus comprises an evaporator element 1 disposed within chamber a, a pump or compressor 2 driven by a suitable prime-mover such as electric motor 3 as by a belt 3a and adapted to withdraw vaporized refrigerant from evaporator 1 through a pipe 4 and discharge the same at higher temperature and pressure into a condenser 5 which returns the condensed refrigerant to evaporator 1 through a float-type expansion valve or feeder 6. The connection between condenser 5 and feeder 6 includes a liquid trap or seal which may be provided by a U tube 7 of relatively small bore. Evaporator 1 may be of any suitable 'or desired type and may be arranged to freeze liquid in suitable trays 8 as well as to maintain storage chamber a at the desired low temperature. Evaporator 1 is preferably constructed with a storage cham-' ber 10 to take care of variations in the liquid level of the refrigerant and to prevent the same from passing as liquid into compresser2.

Feeder 6 is disposed at such a height relative to evaporator 1 that the float valve 6a in the feeder operates not from the level of the liquid in the evaporator 1 but from the level of the liquid in the float chamber 6?) of the feeder which is connected to the condenser through the previously mentioned U tube or trap 7. Any suitable or desired means (not shown) for automatically starting and stopping the prime mover 3 in response to temperature changes in chamber a or in response to pressure changes in the system or for otherwise putting the apparatus into or out of operation may be provided.

It is essential to the operation of my imp'oved process that the condenser and piping so constructed and arranged that when the machine is shut down all the liquid will be forced to 0 into the low temperature zone leaving t e warm ortion of the high side of the system in a, ry condition. Perhaps the easiest way to insure this result is to place the compressor and condenser above the feeder and evaporator and arrange the,

connection so that all liquid will drain by gravity into the low temperature zone within refrigerator A.

Since the disclosed apparatus operates on the Rankine-cycle it will be apparent that the volatile refrigerant fluid in evaporator l is caused to evaporate through the action of compressor 2, the vapor drawn oif by the latter being forced at higher temperature and pressure into condenser 5 where heat is removed and the vapor causedto condense, the condensate being fed back into the evaporator through feeding device 6. The present invention is concerned particularly with the phenomena which occur when the apparatus is shut down, and which involve the process of reducing the pressure on the high side of the system in order to relieve the load on compressor when the system is again put into operation. When the compressor shuts down, all condensate in condenser 5 drains out of the zone of the high temperature, i. e. out of the apparatus disposed outside of refrigera tor cabinet A, into the low temperature zone which is inside cabinet A. The high side system above trap 7 accordingly dries out and all of the liquid refrigerant in the system is brought into thermal intimacy with evaporator 1 with the result that the vaporization of refrigerant fluid at room temperature, such as occurs in similar outfits as heretofore constructed, is entirely avoided. Moreover, the draining of the condensate into tra 7 raises the liquid level in float valve chain er 6b so that float valve 611 rises from its seat and permitsthe condensate in trap 7 and in chamber 6b to pass over into evaporator 1, header 1a taking care of the increased amount of liquid in the evaporator, so that an equalization of pressure occurs between the high and low sides of the system and the pressure on the high side falls substantially to the pressure obtaining onthe low side. The normal level of liquid is evaporator 1 when the apparatus is in operation is indicated in full lines and the higher liquid level which develops when the apparatus shuts down is indicated by the broken line.

It will be noted that the surface of the liquid in the U tube forming trap 7, which liquid is kept cold by proximity to the evaporator, may be exposed to warm vapor in the condenser during the running period.

This would at first thought seem to cause a considerable loss of efliciency as it might appear that the U tube trap 7 and float chamber 6?) would do the condensing and put heat back into refrigerator chamber A. It is found, however, that when the area of liquid in contact with its vapor is small, the liquid may be cooled far below the temperature of the vapor with only a negligible amount of condensation taking place thereon. This principle is utilized by making the U tube of small bore, for example f which, however. is sufliciently large to quickly pass any normal supply of liquid reaching it from the condenser. The area of cold liquid at the end of the U tube facing the condenser is thus too small to have any effect during the normal operation of the system and the vapor pressure at its surface falls when the condenser is no longer functioning, as during the shut down periods. It is obvious that little, if any, actual loss of efliciency occurs through the draining of the relatively warm liquid out of the high side into the evaporator after the machine stops since the liquid eventually must go throu h this step of the cycle.

The form 0 apparatus herein SllOWn and described is merely for the purpose of illustrating the invention and it will be obvious to those skilled in the art that the invention is capable of varied forms and adaptions. It is, accordingly, to be understood that the invention is not limited to the specific details shown, but covers all changes, modifications. adaptations and variations within the scope of the appended claims.

I claim as my invention:

1. In combination, a cabinet, and refrigerating apparatus of the closed cycle type operating on the Rankine cycle associated with said cabinet, said apparatus being so constructed and arranged that all liquid refrigerant is moved into and stored within said cabinet during the shut down periods of said apparatus, and means restricting the area of contact between the liquid and vapor phases of the refrigerant.

2. In combination, a refrigerator cabinet, apparatus of the closed cycle type operating on the Rankine cycle associated with said cabinet including an evaporator within said cabinet and a compressor and a condenser outside said cabinet, said compressor and said condenser being so disposed relative to said evaporator that all liquid refrigerant in the same moves into said cabinet during shut down periods, and a conduit of restricted size establishin alimited area of contact between the liqui and vapor phases of the refrigerant.

3. Refrigeratingapparatus operating on the Rankine cycle comprising a compressor, a condenser, a feeding device, and an evaporator connected together to form a closed cycle system, and means intermediate said condenser and said evaporator for moving all condensate into thermal intimacy with said evaporation when said compressor is not operating including a conduit providing a restriction at the point of contact of the liquid and vapor phases of the refrigerant.

4. Refrigerating apparatus of the closed cycle type operating on the Rankine cycle comprising an evaporator, a compressor, a condenser, a liquid feeding device between said condenser and said evaporator, and a liquid trap between said device and said condenser, said device and trap being in thermal con-densate into said evaporator when the intimacy with said evaporator.

5. Refrigerating apparatus of the closed cycle type operating on the Rankine cycle comprising an evaporator, a compressor, a condenser, a liquidfeeding device between said condenser and said evaporator, and means forming a trap for liquid between said device and said condenser, said means resenting a restricted surface area of liqui to said condenser.

6. Refrigerating apparatus of the closed cycle type operating on the Rankine cycle comprising an evaporator, a compressor, a condenser, a liquid feeding device for said evaporator, and a U tube of small bore between said device and said condenser and forming a trap for liquid.

7. In combination, a refrigerator cabinet, apparatus of the closed cycle type operating on the Rankine cycle associated with said cabinet including an evaporator within said cabinet and a compressor and a condenser outside said cabinet, said condenser being so disposed relative to said evaporator that condensate in the former will move by gravity toward the latter, and means permittin all the condensate to pass into said refrigerator cabinet when the apparatus is shut down and reducing to a minimum the area of contact between the liquid and vapor phases of therefrigerant. r

8. In combination, a refrigerator cabinet, apparatus of the. closed cycle type operating on the Rankine cycle associated with sai cabinet including an evaporator within said cabinet and a compressor and a condenser outside said cabinet, saidscondenser being so disposed relative to said evaporator that all condensate in the former will move by gravity toward the latter, and a float device controlling the feeding of condensate to said evaporator and permitting movement of the system shuts down, the connection from said condenser to said device forming a trap for densate in the formerwill move'by gravity toward the latter, a float device within said cabinet controlling the feeding of the condensate to said evaporator and permitting movement of the condensate into said evaporator when the s stem shuts down, and a U tube of restricted bore ad acentsaid device and forming a liquid trap etween the latter and said condenser.

10. A self contained refrigerating outfit comprising a refrigerator and apparatus associated therewith for extracting heat therefrom and arranged for automatic .or manual control, said apparatus operating on the Rankine c cle and comprising a compressor and a con enser upon the exterior of the refrigerator and a prime mover for said compres'sor, within said refrigerator an evaporator and liquid feeding device therefor, said condenser and compressor being so dis osed that during shut down periods all quid refrigerant moves into the parts of the apparatus within the refrigerator, and means establishing between said condenser and said device at the point of contact of the liquid and vapor phases of the refrigerant.

11. A self contained refrigerating outfit comprising a refrigerator and ap aratus associated therewith for extracting lieat therefrom and arranged for automatic or manual control, said apparatus operating on the Rankine cycle and comprising a compressor and a condenser upon t e exterior of the refrigerator, a prime. mover for said compressor, and within said refrigerator an evaporator and a float feedingdev1ce,.a liquid tra an disposed within said refrigerator, said condenser and compressor being arranged to cause liquid refrigerant to move by gravity into the parts within said refrigerator.

12. A self contained refrigerating outfit comprising a refrigerator and ap aratus associated therewith for extracting eat therefrom and arranged for automatic or manual control, said ap aratus operating on the Rankine cycle an comprising a compressor and a condenser upon t e exterior of the refrigerator, a prime mover for said compressor, and within said refrigerator an evaporator and a float feeding device controlled independently of the liquid level in said evaporator, a U tube of restricted bore within said refrigerator adjacent said dea restriction in the connection between said device and said condenser vice and forming a traiped connection from said device to sand con enser, said condenser being dis osed at a, higher level than the parts within the said refri erator to cause 5 condensate to drain into the ow tem rature portion of the system during shut own periods.

Signed b me at Detroit, in the county of Wa ne, an State of Michigan, this 14th day of anuary, 1927.

RANSOM W. DAVENPORT. 

